解决办法：

（1）关于Fan Noise，：

由于只有这一个是用于噪音的，所以我认为是适用于所有风机的噪音。

（2）domain部分帮助文档的解释是： The domain in which the blade is located

（3）Blade Selection: Set to Automatic for a single blade passage or Custom for a multiple blade passage. If this is set to Custom, you will need to specify the 2D region for the blade (Custom Blade) as well as the number of blades (Custom # Blades).

（4）# of Harmonics: The number of harmonics used in the calculation.

（5）Observer (r) and Observer (theta): The distance and location of the observer, relative to the blade.

（6）Theta Sectors: The number of sampling points (sectors) equally spaced over 360° at a given radius around the fan, used to calculate the noise values. A higher number leads to a more accurate solution, but takes more time to calculate.

（7）Directivity Harm. #: The harmonic level at which the sound pressure levels will be calculated.

（8）Loading Coeff.: A coefficient between 2 and 2.5.